Abstract: Objective To analyze the expression of Keratin 17 (KRT17) in colorectal cancer (CRC) and its clinical prognostic value. Methods Bioinformatics methods were employed to analyze the expression of KRT17 in the CRC database and its prognostic value. Furthermore, the expression level of KRT17 protein in 95 pairs of CRC samples was evaluated by immunohistochemistry (IHC), and the relationships between the KRT17 expression and clinicopathological features and prognosis of patients with CRC were investigated. Results Bioinformatics analysis revealed that the expression level of KRT17 in CRC tissues was significantly higher than that in normal tissues. The expression of KRT17 was correlated with tumor pathological type, lymph node metastasis, and TNM stage, and its overexpression predicted poor overall survival (allP< 0. 05). IHC showed that the expression of KRT17 protein was significantly up-regulated in CRC tissues as compared with that in adjacent-tumor tissues (t = 45. 704, P< 0. 001), which was consistent with the results from bioinformatics analysis. High expression of KRT17 was significantly correlated with tumor grade, depth of tumor invasion, lymph node metastasis, TNM stage, lymphovascular invasion, and perineural invasion (all P< 0. 05). Moreover, the survival analysis demonstrated that the overall survival of CRC patients with high expression of KRT17 was significantly lower than that of CRC patients with low expression of KRT17 (χ 2 = 8. 510, P = 0. 004), and further univariate and multivariate analyses indicated that high expression of KRT17 was an independent risk factor for overall survival of CRC patients (HR: 2. 015, 95 % CI: 1. 219-4. 457, P = 0. 018). Conclusion KRT17 is significantly up-regulated in CRC tissues, and its high expression predicts tumor progression and poor prognosis. KRT17 is expected to become a promising biomarker for prognosis evaluation of CRC patients.

Key words: colorectal cancer, Keratin 17, bioinformatics analysis, immunohistochemistry, prognosis